Loading robots are typically used to load tape cartridges into their respective slots in tape libraries. In order to store as many tape cartridges as possible in a tape library, it is desirable to minimize the space occupied by each slot so as to maximize the number of slots that may be provided in a tape library of a given form factor.
For a small slot size, it is necessary for the loading robot to have precise positioning capabilities so as to be able to correctly insert the tape cartridge with little clearance between the slot and the tape cartridge. It is also desirable for the loading robot to have a low profile so as to take up less space in the tape library and allow more room for storage.
Currently, loading robots are typically driven by linear slides or belt drives. These are adapted to move a tray supporting a tape cartridge up and down with respect to vertical posts. The loading robot also moves horizontally along a defined path of the tray. The tray has to stop at specific heights with great accuracy to enable the loading robot to deposit a tape cartridge into a slot since the slots in a tape library are normally vertically stacked into columns of slots.
There are limitations to using linear slides or belt drives for moving the tray in a loading robot. Although accurate, linear slides are costly to implement. Belt drives are known to stretch after a period of use, thereby losing precision.
To increase storage in a tape library without substantial increases in costs, there thus needs to be a low-cost, precise and robust transmission system to enable the loading robot to work with storage slots that occupy less space.